From 64d260f6473a45c8756af00620169c071fb1e563 Mon Sep 17 00:00:00 2001
From: Walter Bright <walter@walterbright.com>
Date: Wed, 1 May 2024 20:08:25 -0700
Subject: [PATCH] Fix ref on function param

---
 changelog/dmd.reflocal.dd                 | 8 +++++---
 compiler/src/dmd/dsymbolsem.d             | 4 ++--
 compiler/src/dmd/escape.d                 | 4 ++--
 compiler/test/fail_compilation/diag9679.d | 5 ++---
 4 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/changelog/dmd.reflocal.dd b/changelog/dmd.reflocal.dd
index c3ce216c45..9732ef0d19 100644
--- a/changelog/dmd.reflocal.dd
+++ b/changelog/dmd.reflocal.dd
@@ -2,11 +2,13 @@
 
 For example, one can now write:
 ```
+struct S { int a; }
+
 void main()
 {
-    int i;
-    ref int r = i;
+    S s;
+    ref int r = s.a;
     r = 3;
-    assert(i == 3);
+    assert(s.a == 3);
 }
 ```
diff --git a/compiler/src/dmd/dsymbolsem.d b/compiler/src/dmd/dsymbolsem.d
index b2a7e1153e..90b01cdbf9 100644
--- a/compiler/src/dmd/dsymbolsem.d
+++ b/compiler/src/dmd/dsymbolsem.d
@@ -1105,8 +1105,8 @@ private extern(C++) final class DsymbolSemanticVisitor : Visitor
             }
         }
 
-        if ((dsym.storage_class & (STC.ref_ | STC.field)) == STC.ref_ && !dsym._init)
-            .error(dsym.loc, "%s `%s` - initializer is required for `ref` variable", dsym.kind, dsym.toPrettyChars, dsym.type.toChars());
+        if ((dsym.storage_class & (STC.ref_ | STC.field | STC.parameter | STC.temp | STC.foreach_)) == STC.ref_ && !dsym._init && dsym.ident != Id.This)
+            .error(dsym.loc, "%s `%s` - initializer is required for `ref` variable", dsym.kind, dsym.toPrettyChars);
 
         FuncDeclaration fd = parent.isFuncDeclaration();
         if (dsym.type.isscope() && !(dsym.storage_class & STC.nodtor))
diff --git a/compiler/src/dmd/escape.d b/compiler/src/dmd/escape.d
index 1631602952..672b70baa6 100644
--- a/compiler/src/dmd/escape.d
+++ b/compiler/src/dmd/escape.d
@@ -1956,9 +1956,9 @@ void escapeByRef(Expression e, EscapeByResults* er, bool live = false, bool retR
         auto v = e.var.isVarDeclaration();
         if (v)
         {
-            if (v.storage_class & STC.ref_ && v.storage_class & (STC.foreach_ | STC.temp) && v._init)
+            if (v.storage_class & STC.ref_ && v._init)
             {
-                /* If compiler generated ref temporary
+                /* If ref
                     *   (ref v = ex; ex)
                     * look at the initializer instead
                     */
diff --git a/compiler/test/fail_compilation/diag9679.d b/compiler/test/fail_compilation/diag9679.d
index e2614a7306..fb0dd8aa92 100644
--- a/compiler/test/fail_compilation/diag9679.d
+++ b/compiler/test/fail_compilation/diag9679.d
@@ -3,12 +3,12 @@ TEST_OUTPUT:
 ---
 fail_compilation/diag9679.d(15): Error: variable `diag9679.main.n` - storage class `auto` has no effect if type is not inferred, did you mean `scope`?
 fail_compilation/diag9679.d(16): Error: variable `diag9679.main.S.a` - field declarations cannot be `ref`
-fail_compilation/diag9679.d(23): Error: returning `r` escapes a reference to local variable `r`
-fail_compilation/diag9679.d(30): Error: returning `r` escapes a reference to local variable `r`
+fail_compilation/diag9679.d(23): Error: returning `r` escapes a reference to local variable `i`
 ---
 */
 
 
+
 void main()
 {
     if (ref n = 1) {}
@@ -54,4 +54,3 @@ void test5()
 {
     ref int r5;
 }
-